Field of Invention
The present invention relates to separation of desired target products from numerous hydrocarbon containing materials, including biological products produced by cells, insects and/or microorganism in a culture medium; and fuels, such as ethanol, biobutanol, propanol and biodiesel from multiple sources including biological biomass, plant biomass, waste matter including cellulose materials, etc., wherein the separation of the desired target products is conducted with a cross-flow filtration system having the ability to the separate desired target products from both viscous and non-viscous medium.
Related Art in Technical Field
Throughout the world more and more companies are looking to recover value added products from a wide variety of starting materials that include hydrocarbons, such as plants, roots, root crops, grains, flowers, animal tissue, cell cultures comprising yeast, algal, bacteria, or fungi species, milk, milk products, fruits and fruit juices. Several biofuel routes have been pursued including: gasification of biomass to biogas, pyrolysis of biomass to oils, direct liquefaction, conversion of plant oils to biodiesel and release of sugars for fermentation to ethanol. Further, companies are looking to extract value added products from solid and liquid waste streams such as mill and grain wash waters, fermentation biomass and manure. One such waste stream includes biomass from bio-fuel production which, during the process and after production of fuels such as diesel and alcohol, is rich in plant proteins, sugars, oils and carbohydrates. Another such waste stream is cellular biomass used for protein and essential fatty acids production from wild and/or recombinant yeast, algae, bacteria, larvae or fungi species.
The production of materials in biotechnology and renewal energy involves the isolation, separation, and/or purification of a specific target molecule that is surrounded by many other biological components. It does not matter whether the material comes from fermentation processes or yard waste, the material of interest must be collected in a reasonably pure form.
The culturing of microorganisms, insect larvae, microbial cells (fermentation) or animal and plant cells (tissue culture) are central to a multiplicity of commercially-important chemical and biochemical production processes. Microorganisms, insect larvae and living cells are employed in these processes as a result of the fact that all can economically synthesize commercially-valuable chemicals. The desired product(s) can be either purified from the liquid medium or extracted from the cells themselves.
Biofuels, such as ethanol or biobutanol have widespread application as industrial chemical, gasoline additive or straight liquid fuel. As a fuel or fuel additive, both ethanol and biobutanol dramatically reduces air emissions while improving engine performance. As a renewable fuel, they reduce national dependence on finite and largely foreign fossil fuel sources while decreasing the net accumulation of carbon dioxide in the atmosphere. Such biofuels can be produced by multiple sources including microorganisms or derived from other materials that includes components such as cellulose, hemicellulose, lignin, protein and carbohydrates such as starch and sugar. Ethanol typically has been produced from sugars derived from feedstocks high in starches and sugars, such as corn. Recently, other forms including biomass from microorganisms, trees, shrubs and grasses, corn and corn husks, animal waste including manure, as well as municipal solid waste, waste paper and yard waste have been used in the production or isolation of ethanol and biobutanol.
The basic steps of biofuel production from cellulose include hydrolysis of biomass to sugars and then subsequent fermentation of sugars to ethanol. However, there are several places in the process where there are bottlenecks for efficient production of ethanol from these less expensive cellulosic wastes. Specifically, these bottlenecks include inhibitory effect of ethanol on microorganisms (inhibition due to changes in fluidity of biological membranes) and limitations on flow rate for continuous process because of the viscosity or bulk of the liquid medium. One approach to process improvement would be using a continuous fermentation integrating an ethanol removing/recovery operation, thereby maintaining the ethanol concentration in the fermentation broth at a level which is minimally inhibitory to fermenting organisms.
Attempts to address the issue of high feedstock prices have included use of less expensive feed stocks. Cellulosic biomass (agricultural waste/residue etc.) can be used for conversion to ethanol as a less expensive feedstock alternative to corn. However, it has been found that biomass and cell cultures that include highly viscous materials are far more difficult to process, such that, even though the cell culture is five (5) times denser the yield of final product is only 50% greater because the viscosity of the material prevents the separation of the desired target molecule from the mass of cellular materials. In the case of extracts of solid phase material, such as plants and animal tissue, the problem is the same such that the viscous materials clog filters and block chromatography columns as well as not separating efficiently under normal centrifugal forces.
Although it would appear that a simple dilution of the viscous material would solve the problem, this creates at least four additional problems: 1) the cost of the diluent which can be highly expensive in the case of diluents for pharmaceutical intended for human injection, 2) disposal of the higher volume of the waste stream, i.e. the original volume plus the volume of diluent, 3) the cost of the necessary tanks and mixing equipment in order to dilute the starting material, and 4) additional purification costs for the diluted final product.
Thus, when the starting mixture is very complex, isolation of the material of interest can be especially difficult and often requires costly operations. Technologies that reduce the number of separation operations and simplify recovery procedures are in high demand in biotechnology and several other industries including water treatment, ethanol production, food and beverage, and chemicals. As such, there is a need for an improved and less costly separation system that is suitable for large-scale isolation of components of interest from a complex and/or viscous sample.